我在将 wmv 文件转换为 mp4 时遇到问题。我正在使用 x264.exe 这个命令来获取视频流x264 --output temporal.264 --fps 25 --preset slow --bitrate 2048 --vbv-maxrate 2048 --vbv-bufsize 9600 --min-keyint 48 --keyint 48 --scenecut 0 --no-scenecut --pass 1 --video-filter "resize:width=640,height=480" Original.wmv
然后我使用 ffmpeg.exe 用这一行提取音频流:ffmpeg -i .wmv -acodec libfdk_aac -b:a 32000 temporal.aac
最后我使用 MP4Box 将每个流与这一行合并:MP4Box -add temporal.264 Final.mp4
MP4Box -add temporal.aac Final.mp4
问题是 final.mp4 音频不同步。它开始很好，但随着时间的推移，它与时间不同步。
我运行这个命令:MP4Box -info 010004470063PE-10022017083824-2_MultiMedia--1.mp4
我发现两个流的估计时间不同:
命令的输出* Movie Info *
Timescale 600 - 2 tracks
Computed Duration 01:00:03.643 - Indicated Duration 01:00:03.643
Fragmented File: no
File suitable for progressive download (moov before mdat)
File Brand isom - version 1
Compatible brands: isom avc1
Created: GMT Wed Jun 27 16:31:44 2018
Modified: GMT Wed Jun 27 16:31:44 2018
File has root IOD (9 bytes)
Scene PL 0xff - Graphics PL 0xff - OD PL 0xff
Visual PL: AVC/H264 Profile (0x7f)
Audio PL: AAC Profile @ Level 2 (0x29)
No streams included in root OD
Track # 1 Info - TrackID 1 - TimeScale 25000
Media Duration 00:59:57.520 - Indicated Duration 00:59:57.520
Track has 1 edit lists: track duration is 00:59:57.320
Media Info: Language "Undetermined (und)" - Type "vide:avc1" - 89938 samples
Visual Track layout: x=0 y=0 width=640 height=480
MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
AVC/H264 Video - Visual Size 640 x 480
AVC Info: 1 SPS - 1 PPS - Profile Main @ Level 3
NAL Unit length bits: 32
Chroma format YUV 4:2:0 - Luma bit depth 8 - chroma bit depth 8
SPS#1 hash: 41EE779BEF2AA71A7131EAFD3C77C7E3BC95FD8E
PPS#1 hash: 086E1D72A40A0E8CF35D102F34A9DF6CD44D6CEF
Self-synchronized
RFC6381 Codec Parameters: avc1.4D401E
Average GOP length: 250 samples
Track # 2 Info - TrackID 2 - TimeScale 44100
Media Duration 01:00:03.644 - Indicated Duration 01:00:03.644
Media Info: Language "Undetermined (und)" - Type "soun:mp4a" - 155196 samples
MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x40
MPEG-4 Audio AAC LC - 2 Channel(s) - SampleRate 44100
Synchronized on stream 1
RFC6381 Codec Parameters: mp4a.40.2
All samples are sync
我不支持为什么会发生这种情况，因为原始的 wmv 是完全同步的。有什么帮助吗？
最佳答案
.aac是一个没有时间戳的原始容器，如果源音频中存在 PTS 间隙，它们将丢失。
您有两种解决方法:
a) 提取到定时 sample 容器
ffmpeg -i .wmv -acodec libfdk_aac -b:a 32000 -vn temporal.m4a
b) 填补空白并提取
ffmpeg -i .wmv -af aresample=async=1 -acodec libfdk_aac -b:a 32000 temporal.aac
关于windows - 为什么我的 mp4 文件的音频不同步，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51108865/